Detection efficiency of alpha particles emitted by 222rn and 222rn progeny (218po and 2l4po) in the air of the diffusion chamber under the influence of an electret

Detection efficiency of alpha particles emitted by radon-222 in the air of the diffusion chamber under the influence of an electrets have been carried out by using solid state nuclear track detector LR-115, type II. Electrets are the electrostatic equivalent of permanent magnet, having a permanent surface charge resulting in a surface potential that may be several KV. Electrets were used to attract radon progeny formed in a cylindrical shape diffusion cup where solid state nuclear track detector LR-115, type II was placed for the measurement of radon concentration. In this way the sensitivity of detector could be increased by bringing progeny just in front of detector in more convenient measuring geometry. It was found that the detection efficiency of α-particle emitted by radon only in the air of diffusion chamber increases with the distance at 5.45 Mev for five hours and ten hours respectively where as the detection efficiency of α-particle emitted by radon progeny in the air of diffusion chamber decreases with the distance at 6.49MeV and7.59MeV for five hours and ten hours respectively. Influence of distance between electret and detector on sensitivity of such equipment has been investigated theoretically. It was also found that in the analysis that the radon progeny 218Po and 2l4Po just have the same detection efficiency of 25% when the electret is closed to the LR-115 detector.